Solve for $x$. Enter the solutions from least to greatest. $5x^2 + 15x - 140 = 0$ $\text{lesser }x = $
Answer: $\begin{aligned} 5x^2 + 15x - 140 &= 0 \\\\ 5(x^2+3x-28)&=0 \end{aligned}$ Now let's factor the expression in the parentheses. $x^2+3x-28$ can be factored as $(x+7)(x-4)$. $\begin{aligned} 5(x+7)(x-4)&=0 \\\\ x+7=0&\text{ or }x-4=0 \\\\ x=-7&\text{ or }x=4 \end{aligned}$ In conclusion, $\begin{aligned} \text{lesser }x &= -7 \\\\ \text{greater }x &= 4 \end{aligned}$